Reforming device and reforming method, and device for manufacturing chemical products equipped with reforming device and method for manufacturing chemical products

ABSTRACT

A reforming device according to the present invention has a compressor, a first heat exchanger, a desulfurization device, a reformer, a raw material gas branching line that extracts a compressed natural gas from a downstream side of the desulfurization device with respect to the flow direction of the natural gas and supplies the natural gas to the reformer, and a flue gas discharging line that discharges a flue gas generated in the reformer, wherein the first heat exchanger is provided in the flue gas discharging line, and the flue gas is used as a heating medium of the compressed natural gas.

FIELD

The present invention relates to a reforming device that reforms anatural gas by using the natural gas as a fuel of a reformer forreforming the natural gas or the like, and a device for manufacturingchemical products equipped with the same.

BACKGROUND

When manufacturing methanol and ammonia, a reformed gas obtained byreforming the natural gas or the like in the reformer is used (forexample, see Patent Literatures 1 and 2). When the natural gas or thelike is reformed in the reformer to convert the natural gas to thereformed gas, before supplying the natural gas to the reformer, a partof the natural gas is extracted and used as fuel of the reformer, andthe natural gas supplied to the reformer is reformed.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Laid-open Patent Publication No. 6-234517

Patent Literature 2: Japanese Laid-open Patent Publication No.2000-63115 (Japanese Patent No. 4168210)

SUMMARY Technical Problem

As in Patent Literatures 1 and 2, in the method for manufacturingmethanol and ammonia which have been conventionally used, in general,the natural gas is first compressed to a reforming pressure. Moreover, apart of the natural gas which has not been desulfurized is extractedbefore compressing the natural gas and is used as fuel of the reformer.Thereafter, for improving production efficiency of methanol and ammonia,in order to improve a quantity of heat recovery from the reformer fluegas and improve the thermal efficiency when reforming the natural gas,there is a need to further improve the reforming device.

The present invention has been made in view of the above-describedproblems, and an object thereof is to provide a reforming device and areforming method capable of improving the thermal efficiency whenreforming the natural gas, a manufacturing device of chemical productsequipped with the reforming device, and a method for chemical products.

SOLUTION TO PROBLEM

According to a first aspect of the present invention in order to solvethe above-mentioned problems, there is provided a reforming deviceincluding: a first compression unit that compresses a raw material gascontaining hydrocarbon and sulfur; a first heat-exchange unit that heatsthe compressed raw material gas; a desulfurization unit that removessulfur content contained in the heated raw material gas; a reformingunit that reforms the hydrocarbon in the raw material gas to either oneor both of H₂ and CO or H₂ and CO₂ to generate a reformed gas containingeither one or both of H₂ and CO or H₂ and CO₂; a raw material gasbranching line that extracts a part of the compressed raw material gasfrom either one or both of an upstream side and a downstream side of thedesulfurization unit with respect to a flow direction of the rawmaterial gas, and supplies the part of the compressed raw material gasas a combustion fuel used for heating in the reforming unit; a flue gasdischarging line that discharges a flue gas, which is generated bycombustion in the reforming unit, from the reforming unit; and a secondheat-exchange unit that heat-exchanges the combustion air used forheating in the reforming unit with the flue gas which is heat-exchangedin the first heat exchange unit, wherein the first heat exchange unit isprovided in the flue gas discharging line, and the flue gas is used as aheating medium of the compressed raw material gas, and the second heatexchange unit is provided on the downstream side of the first heatexchange unit of the flue gas discharging line, and is used as theheating medium of the combustion air by residual heat which isheat-exchanged in the first heat exchange unit.

According to a second aspect of the present invention, there is providedthe reforming device according to the first aspect, wherein thereforming unit has a first reforming unit that supplies vapor to the rawmaterial gas to primarily reform the hydrocarbon in the raw material gasto either one or both of H₂ and CO or H₂ and CO₂, and a second reformingunit that secondarily reforms the hydrocarbon in the raw material gasafter the primary reforming in the first reforming unit to either one orboth of H₂ and CO or H₂ and CO₂ to be a reformed gas, using thecombustion air and the compressed raw material gas supplied from the rawmaterial gas branching line.

According to a third aspect of the present invention, there is providedthe reforming device according to the first or second aspect, wherein athird heat exchanger configured to heat-exchange feed water supplied toa steam generation unit with the flue gas is provided between the firstheat exchange unit and the second heat exchange unit.

According to a fourth aspect of the present invention, there is providedthe reforming device according to the third aspect, further including: afourth heat exchanger that is provided in the raw material gas branchingline to heat-exchange the compressed raw material gas before beingintroduced into the first heat exchanger with a part of the branched rawmaterial gas.

According to a fifth aspect of the present invention, there is providedthe reforming device according to any one of the first to fourthaspects, including any one or both of: a denitrification unit that isprovided between the reforming unit of the flue gas discharging line andthe heat exchange unit to remove NOx contained in the flue gas that isgenerated in the reforming unit; and a CO₂ recovery unit that isprovided on the downstream side of the heat exchange unit with respectto the flow direction of the flue gas of the flue gas discharging lineto remove CO₂ contained in the flue gas.

According to a sixth aspect of the present invention, there is provideda device for manufacturing chemical products including: the reformingdevice according to any one of the first to fifth aspects; and achemical product generation unit that manufactures chemical productsusing the reformed gas.

According to a seventh aspect of the present invention, there isprovided the device for manufacturing chemical products according to thesixth aspect, wherein the chemical product generation unit is an ammoniasynthesis unit that synthesizes ammonia using the reformed gas which hasbeen reformed.

According to an eighth aspect of the present invention, there isprovided the device for manufacturing chemical products according to theseventh aspect, wherein the chemical product generation unit is a ureasynthesis unit that synthesizes urea using the obtained ammonia.

According to a ninth aspect of the present invention, there is providedthe device for manufacturing chemical products according to the sixthaspect, wherein the chemical product generation unit is a methanolsynthesis unit that synthesizes methanol using the reformed gas whichhas been reformed.

According to a tenth aspect of the present invention, there is provideda reforming method including: a first heat-exchange step of heating araw material gas containing compressed hydrocarbon and sulfur; adesulfurization step of removing sulfur content contained in the heatedraw material gas; a reforming step of reforming the hydrocarbon in theraw material gas to either one or both of H₂ and CO or H₂ and CO₂ togenerate a reformed gas containing either one or both of H₂ and CO or H₂and CO₂; and a second heat-exchange step of heat-exchanging a combustionair used for heating in the reforming step with the flue gas that isheat-exchanged in the first heat-exchange step, wherein the compressedraw material gas is extracted from either one or both of an upstreamside and a downstream side of the desulfurization step with respect to aflow direction of the raw material gas, and is supplied as a combustionfuel used for heating in the reforming step, and the flue gas generatedby combustion in the reforming step is discharged from the reformingstep, the flue gas is subjected to a first heat-exchange by being usedas a heating medium of the compressed raw material gas, and the flue gasof residual heat after heat-exchange of the compressed raw material gasis subjected to a second heat-exchange as a heating medium of thecombustion air.

According to an eleventh aspect of the present invention, there isprovided the reforming method according to the tenth aspect, wherein athird heat-exchange step of heat-exchanging feed water supplied to asteam generation unit with the flue gas is provided between the firstheat-exchange step and the second heat-exchange step.

According to a twelfth aspect of the present invention, there isprovided the reforming method according to the eleventh aspect, furtherincluding: a fourth heat-exchange step that is provided in the rawmaterial gas branching line to heat-exchange the compressed raw materialgas introduced into the first heat-exchange step with a part of thebranched raw material gas.

According to a thirteenth aspect of the present invention, there isprovided a method for manufacturing chemical products including: thereforming step according to any one of the tenth to eleventh aspects;and a chemical product generation step of manufacturing chemicalproducts using the reformed gas.

According to a fourteenth aspect of the present invention, there isprovided the method for manufacturing chemical products according to thethirteenth aspect, wherein the chemical product generation step is anammonia synthesizing step of synthesizing ammonia using the reformed gaswhich has been reformed.

According to a fifteenth aspect of the present invention, there isprovided the method for manufacturing chemical products according to thefourteenth aspect, wherein the chemical product generation step is aurea synthesizing step of synthesizing urea using the obtained ammonia.

According to a sixteenth aspect of the present invention, there isprovided the method for manufacturing chemical products according to thethirteenth aspect, wherein the chemical product generation step is amethanol synthesizing step of synthesizing methanol using the reformedgas which has been reformed.

Advantageous Effects of Invention

According to the present invention, since it is possible to improve thequantity of heat recovery from the heat medium to the natural gas whenheating the natural gas, it is possible to improve the thermalefficiency when reforming the natural gas.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of a reforming device according to a firstembodiment of the present invention.

FIG. 2 is a schematic diagram of the reforming device according to thefirst embodiment of the present invention.

FIG. 3 is a schematic diagram of another reforming device according tothe first embodiment of the present invention.

FIG. 4 is a schematic diagram of another reforming device according tothe first embodiment of the present invention.

FIG. 5 is a schematic diagram of another reforming device according tothe first embodiment of the present invention.

FIG. 6 is a schematic diagram of another reforming device according tothe first embodiment of the present invention.

FIG. 7 is a schematic diagram of another reforming device according tothe first embodiment of the present invention.

FIG. 8 is a schematic diagram of another reforming device according tothe first embodiment of the present invention.

FIG. 9 is a diagram illustrating an example of a system configuration ofthe reforming device illustrated in FIG. 1.

FIG. 10 is a diagram illustrating an example of a system configurationof the reforming device illustrated in FIG. 3.

FIG. 11 is a schematic diagram of a chemical product manufacturingdevice equipped with a reforming device according to a second embodimentof the present invention.

FIG. 12 is a schematic diagram of a chemical product manufacturingdevice equipped with another reforming device according to the secondembodiment of the present invention.

FIG. 13 is a schematic diagram of a chemical product manufacturingdevice equipped with another reforming device according to the secondembodiment of the present invention.

FIG. 14 is a schematic diagram of a chemical product manufacturingdevice equipped with another reforming device according to the secondembodiment of the present invention.

FIG. 15 is a schematic diagram of a chemical product manufacturingdevice equipped with another reforming device according to the secondembodiment of the present invention.

FIG. 16 is a schematic diagram of a chemical product manufacturingdevice equipped with another reforming device according to the secondembodiment of the present invention.

FIG. 17 is a schematic diagram of a chemical product manufacturingdevice equipped with another reforming device according to the secondembodiment of the present invention.

FIG. 18 is a schematic diagram of a chemical product manufacturingdevice equipped with another reforming device according to the secondembodiment of the present invention.

FIG. 19 is a schematic diagram of a chemical product manufacturingdevice equipped with another reforming device according to the secondembodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

The present invention will be described in detail below while referringto the drawings. The present invention is not intended to be limited bymodes for carrying out the invention (hereinafter, referred to asembodiments) described below. In addition, constituent elements in theembodiments described below include elements that can be easily assumedby those skilled in the art, substantially identical elements, andelements of the so-called equivalent range. Furthermore, the constituentelements disclosed in the embodiments described below can be suitablycombined with one another.

First Embodiment <Reforming Device>

A reforming device according to a first embodiment of the presentinvention will be described with reference to the drawings. FIG. 1 is aschematic diagram of a reforming device according to the firstembodiment of the present invention. As illustrated in FIG. 1, areforming device 10 has a compressor (compression unit) 11, a first heatexchanger (heat exchange unit) 12, a desulfurization device(desulfurization unit) 13, a reformer (reforming unit) 14, adenitrification device (denitrification unit) 15, a second heatexchanger 16, a cooling device 17, a CO₂ recovery device (CO₂ recoveryunit) 18, a raw material gas branching line L11, and a flue gasdischarging line L12.

In the present embodiment, although a natural gas 21 is used as a rawmaterial gas containing hydrocarbon and sulfur, the raw material gas isnot limited thereto, any raw material gas containing hydrocarbon may beused, and for example, a liquefied petroleum gas (LPG), a synthetic gassuch as butane or naphtha obtained from other hydrocarbon, a natural gasliquid (NGL) produced due to production of crude oil and natural gas,methane hydrate or the like is adopted.

The compressor 11 is intended to compress the natural gas 21, and raisesthe natural gas 21 to a predetermined pressure. The natural gas 21 issupplied to the compressor 11 through a raw material gas supply lineL13-1. After the natural gas 21 is raised to a predetermined pressure inthe compressor 11 to become a high temperature, the natural gas 21 issupplied to the first heat exchanger 12 through the raw material gassupply line L13-2.

The first heat exchanger 12 is intended to heat the compressed naturalgas 21. The first heat exchanger 12 is provided in a flue gasdischarging line L12. As the first heat exchanger 12, for example, aconvection coil type heat exchanger is used. The first heat exchanger 12circulates flue gas 22 inside the duct by setting a duct side as asecondary side, and a tube (heat transfer tube) side of the first heatexchanger 12 is set to a primary side. Moreover, the first heatexchanger 12 circulates the flue gas 22 discharged from the reformer 14as a heating medium inside the duct, as described below. The first heatexchanger 12 uses the flue gas 22 to be supplied to the outercircumference of the heat transfer tube as a heat source, and circulatesthe natural gas 21 inside the heat transfer tube to heat the natural gas21.

In addition, the first heat exchanger 12 is not limited to a convectioncoil type heat exchanger, and any heat exchanger which is capable ofperforming the indirect heat exchange between the natural gas 21 and theflue gas 22 may be used.

After the natural gas 21 is heated by being heat-exchanged with the fluegas 22 in the first heat exchanger 12, the natural gas 21 is supplied tothe desulfurization device 13 through the raw material gas supply lineL13-3.

The desulfurization device 13 is intended to remove the sulfur content(S content), such as hydrogen sulfide (H₂S) contained in the heatednatural gas 21, and organosulfur compound. A conventionally known deviceis used as the desulfurization device 13, and either wet type or drytype can be used. When the desulfurization device 13 is an absorber thatremoves the S content in the natural gas 21 in a wet process, in thedesulfurization device 13, for example, lime slurry (an aqueous solutionprepared by dissolving limestone powder in water) is used as an alkalineabsorbent, and the internal temperature of the absorber is adjusted toabout 30° C. to 80° C. The lime slurry is supplied to the absorberbottom of the desulfurization device 13. The lime slurry supplied to theabsorber bottom of the desulfurization device 13 is sent to a pluralityof nozzles in the desulfurization device 13 via an absorbent feed lineor the like, and is ejected, for example, toward an absorber top side ofthe absorber from the nozzle. When the natural gas 21 rising from theabsorber bottom side of the desulfurization device 13 comes intogas-liquid contact with the lime slurry ejected from the nozzle, the Scontent in the natural gas 21 is absorbed by the lime slurry and isseparated and removed from the natural gas 21. Inside thedesulfurization device 13, the S content in the natural gas 21 generatesa reaction with the lime slurry represented by the following formula(1). Furthermore, the lime slurry, which has absorbed the S content inthe natural gas 21, is oxidized by air (not illustrated) supplied to theabsorber bottom of the desulfurization device 13, and generates thereaction with air represented by the following formula (2). In this way,the S content in the natural gas 21 is captured in the form of gypsumCaSO₄.2H₂O in the desulfurization device 13.

CaCO₃+SO₂+0.5H₂O→CaSO₃.0.5H₂O+CO₂   (1)

CaSO₃.0.5H₂O+0.5O₂+1.5H₂O→CaSO₄.2H₂O   (2)

The natural gas 21 purified by the lime slurry is discharged from theabsorber top side of the desulfurization device 13. Thereafter, thenatural gas 21 is supplied into the reformer 14 through the raw materialgas supply line L13-4. The raw material gas supply line L13-4 isconnected to a vapor supply line L14. A vapor 24 is supplied into theraw material gas supply line L13-4 through the vapor supply line L14,and is mixed with the natural gas 21. After the natural gas 21 is mixedwith the vapor 24 in the vapor supply line L14, the mixture is suppliedinto the reformer 14.

The reformer 14 is intended to reform hydrocarbon in the natural gas 21to either one or both of H₂ and CO or H₂ and CO₂, and generate areformed gas 23 containing either one or both of H₂ and CO or H₂ andCO₂. The reformer 14 has a main body 14 a, a catalyst reaction tube 14b, and a burner 14 c. The catalyst reaction tube 14 b is provided insidethe main body 14 a, and a reforming catalyst layer having a reformingcatalyst is provided inside the catalyst reaction tube 14 b. The burner14 c is provided inside the main body 14 a, and heats the catalystreaction tube 14 b, by combusting a combustion air 26 to generate a fluegas 22. The burner 14 c is connected to the air supply line L15. Thecombustion air 26 is supplied to the burner 14 c through the air supplyline L15. As will be described below, after the combustion air 26 isheated by being heat-exchanged with the flue gas 22 in the second heatexchanger 16, the combustion air 26 is supplied to the reformer 14. Thecatalyst reaction tube 14 b is heated by the flue gas 22, the naturalgas 21 comes into contact with the reforming catalyst when passingthrough the reforming catalyst layer of the catalyst reaction tube 14 b,and thus, as in the following formulas (3) and (4), hydrocarbon in thenatural gas 21 is reformed to H₂ and CO or H₂ and CO₂. Thus, a reformedgas 23 containing either one or both of H₂ and CO or H₂ and CO₂ isproduced. The gas temperature of the reformed gas 23 is in the range of,for example, 400° C. to 1000° C.

CH₄+H₂O→CO+3H₂   (3)

CH₄+2H₂O→CO₂+4H₂   (4)

The raw material gas branching line L11 connects a downstream side ofthe desulfurization device 13 with the air supply line L15. The rawmaterial gas branching line L11 extracts a part of the natural gas 21compressed by the compressor 11 from the downstream side of thedesulfurization device 13 with respect to the flow direction of thenatural gas 21 as a branch gas 21 a, and mixes the branch gas 21 a withthe flue gas 22 passing through the air supply line L15. In regard tothe branched branch gas 21 a, since the S content contained in thenatural gas 21 is removed by the desulfurization device 13, the naturalgas 21 containing no S content is supplied to the air supply line L15.

The reformed gas 23 produced in the reformer 14 is used as a rawmaterial gas for synthesizing hydrogen, liquid hydrocarbon, methanol,ammonia or the like. Also, the flue gas 22 discharged from the reformer14 is supplied to a denitrification device 15 through the flue gasdischarging line L12.

The flue gas discharging line L12 is a line for discharging the flue gas22 which is generated by combusting the fuel containing the natural gas21 extracted to the raw material gas branching line L11 as a fuel, usingthe combustion air 26 in the reformer 14. In the middle of the flue gasdischarging line L12, the denitrification device 15, and a reducingagent injector 28 located on the upstream side of the denitrificationdevice 15 are provided. On the way in which the flue gas 22 passingthrough the flue gas discharging line L12 is supplied to thedenitrification device 15, a reducing agent 29 is supplied to the fluegas 22 from the reducing agent injector 28. As the reducing agent 29,for example, ammonia (NH₃), urea (NH₂(CO)NH₂), ammonium chloride (NH₄Cl)and the like are used. The reducing agent 29 is supplied to the flue gasdischarging line L12 as a solution or gas containing the reducing agent29. When a solution containing the reducing agent 29 is supplied to theflue gas discharging line L12, droplets of the solution containing thereducing agent 29 are vaporized by evaporation by high-temperatureambient temperature of the flue gas 22.

The flue gas 22 is supplied to the denitrification device 15 through theflue gas discharging line L12 in a state of containing the reducingagent 29.

The denitrification device 15 is provided between the reformer 14 of theflue gas discharging line L12 and the first heat exchanger 12 to removethe nitrogen oxides (NOx) contained in the flue gas 22 generated in thereformer 14. As the denitrification device 15, a conventionally knowndevice is used, and for example, as the denitrification device 15, adevice equipped with a denitrification catalyst layer in which adenitrification catalyst for removing NOx in the flue gas 22 is filledis used. When the flue gas 22 supplied into the denitrification device15 comes into contact with the denitrification catalyst filled in thedenitrification catalyst layer, the reduction reaction of NOx in theflue gas 22 on the denitrification catalyst with the reducing agent 29progresses as in the following formula (5) and NOx is reduced, and NOxis decomposed and removed into nitrogen gas (N₂) and water (H₂O).

4NO+4NH₃+O₂→4N₂+6H₂O   (5)

After NOx in the flue gas 22 is removed by the denitrification device15, the flue gas 22 is supplied to the first heat exchanger 12.Moreover, in the first heat exchanger 12, as described above, the fluegas 22 is heat-exchanged with the natural gas 21 to heat the natural gas21. Thereafter, the flue gas 22 is supplied to the second heat exchanger16 from the first heat exchanger 12 through the flue gas dischargingline L12.

The second heat exchanger 16 is intended to heat the combustion air 26.Like the first heat exchanger 12, the second heat exchanger 16 isprovided in the flue gas discharging line L12. As the second heatexchanger 16, like the first heat exchanger 12, a convection coil typeheat exchanger is used. The second heat exchanger 16 circulates the fluegas 22 inside the duct by setting the duct side as a secondary side, andcirculates the combustion air 26 inside the heat transfer tube bysetting the tube (heat transfer tube) side as a primary side. The secondheat exchanger 16 uses the flue gas 22 supplied to the outside of theheat transfer tube as a heat source, and circulates the combustion air26 inside the heat transfer tube to heat the combustion air 26.

After the flue gas 22 is heat-exchanged with the combustion air 26 inthe second heat exchanger 16, the flue gas 22 is supplied to the coolingdevice 17. Also, after the combustion air 26 is heated by beingheat-exchanged with the flue gas 22 in the second heat exchanger 16, thecombustion air 26 is supplied to the reformer 14.

The cooling device 17 is intended to cool the flue gas 22. The coolingdevice 17 is a cooling tower in which a cooling water 30 is circulatedthrough the interior and the exterior. In the cooling device 17, thecooling water 30 is supplied from the tower top side, and the flue gas22 supplied into the tower is cooled by being brought into gas-liquidcontact with the cooling water 30. After the cooling water 30 comes intogas-liquid contact with the flue gas 22, the cooling water 30 is storedin the tower bottom, extracted to the outside, and cooled by the cooler.Thereafter, the cooling water 30 is supplied into the cooling toweragain and is brought into gas-liquid contact with the flue gas 22. Thecooling device 17 may be a device that cools the flue gas 22 by theindirect heat-exchange with the cooling water 30, without being limitedto a device that cools the flue gas 22 by bringing the flue gas 22 intodirect-contact with the cooling water 30.

After the flue gas 22 is cooled by the cooling device 17, the flue gas22 is supplied to the CO₂ recovery device 18.

The CO₂ recovery device 18 is intended to remove CO₂ contained in theflue gas 22. The CO₂ recovery device 18 is provided on the downstreamside of the second heat exchanger 16 with respect to the flow directionof the flue gas 22 of the flue gas discharging line L12. As the CO₂recovery device 18, a conventionally known device can be used. As theCO₂ recovery device 18, for example, it is possible to use a deviceequipped with a CO₂ absorber that absorbs CO₂ of the flue gas 22 in theCO₂ absorbent by gas-liquid contact between amine-based CO₂ absorbentand the flue gas 22 in the absorber, and a regenerator that regeneratesthe CO₂ absorbent by diffusing CO₂ absorbed in the CO₂ absorbent withinthe regenerator. By bringing the flue gas 22 into gas-liquid contactwith the CO₂ absorbent in the CO₂ absorber, CO₂ in the flue gas 22 isabsorbed by the CO₂ absorbent, and CO₂ in the flue gas 22 is removed.After CO₂ contained in the flue gas 22 is removed by the CO₂ recoverydevice 18, the flue gas 22 is released into the atmosphere as a purifiedgas.

Also, the raw material gas branching line L11 connects the downstreamside of the desulfurization device 13 with the air supply line L15, andmixes the natural gas 21 compressed by the compressor 11 with the fluegas 22 passing through the air supply line L15, by extracting thenatural gas 21 from the downstream side of the desulfurization device 13with respect to the flow direction of the natural gas 21. Since the Scontent contained in the natural gas 21 is removed by thedesulfurization device 13, the natural gas 21 containing no S contentcan be supplied to the air supply line L15. As a result, the S contentis not contained in the flue gas 22 discharged from the reformer 14. Asa result, since the S content in the flue gas 22 is a very small amount,an acid dew point temperature itself is lowered. Therefore, since it ispossible to further reduce the flue gas temperature and increase theamount of recovery heat from the flue gas, it is possible to reduce thefuel of the reformer 14.

For example, it is possible to reduce the amount of the natural gas 21,which is used as fuel in the reformer 14, for example, to about 0.7% to8.5%.

That is, in the methods for manufacturing methanol and ammonia which hasbeen conventionally used, as in Patent Literatures 1 and 2, in manycases, in general, a part of the natural gas that has not beendesulfurized is extracted and used as a fuel of the reformer. Therefore,when the quantity of heat recovery of the flue gas increases and thetemperature of the flue gas drops, there is a possibility that sulfuricacid corrosion occurs due to the S content such as sulfuric anhydridecontained in the flue gas in a passage of a piping through which theflue gas passes. The sulfuric acid corrosion refers to a phenomenon inwhich the temperature of the flue gas becomes the dew point temperatureor lower of the acid of the S content such as sulfuric anhydridecontained in the flue gas, the S content contained in the flue gas iscombined with water, becomes sulfuric acid (H₂SO₄) and is condensed,thereby corroding the metal. Therefore, as the material of the pipingthrough which the flue gas passes, it is necessary to use acid-resistingsteel having a high corrosion resistance against acids such as sulfuricacid. In contrast, in the present embodiment, since the flue gas 22discharged from the reformer 14 does not include the S content, even ifthe flue gas 22 is heat-exchanged with the combustion air 26 in thesecond heat exchanger 16 and the temperature of the flue gas 22 drops,it is possible to prevent an occurrence of corrosion in the passage ofthe flue gas discharging line L12 on the downstream side in the gas flowdirection of the flue gas 22 from the second heat exchanger 16 of theflue gas discharging line L12. Therefore, as the material of the fluegas discharging line L12, it is possible to use other materials withoutbeing limited to the acid-resisting steel, and the application scope canbe widened.

Also, in the methods for manufacturing the methanol and ammonia whichhave been conventionally used as in Patent Literatures 1 and 2, inconsideration of the possibility of causing the sulfuric acid corrosionin the passage of the piping through which the flue gas passes, it isnot possible to sufficiently perform the recovery of heat which is heldby the flue gas in the heat exchanger that heat-exchanges the flue gasand the natural gas. Thus, there is a possibility that operating costsof the plant equipment for manufacturing methanol and ammonia increase,and the manufacturing costs of the product increase. In contrast, in thepresent embodiment, since it is possible to suppress an occurrence ofcorrosion in the flue gas discharging line L12 even if the temperatureof the flue gas 22 drops in the second heat exchanger 16, it is possibleto further cool the flue gas 22. Therefore, it is possible to furtherrecover heat, which is held by the flue gas 22 in the second heatexchanger 16, by the combustion air 26, and it is possible to improvethe thermal efficiency of the reforming device 10.

Here, although the heat-exchange in the second heat exchanger 16 is, forexample, 175° C. in view of the acid dew point, it can be lowered to thelower limit value of 120° C. In addition, 120° C. of the lower limitvalue is a flue gas temperature that is determined in consideration ofthe dew point of water.

Furthermore, when the denitrification device 15 or the like is installedin the flue gas discharging line

L12, the reducing agent 29 such as ammonia is supplied to the flue gasduct. However, in the methods for manufacturing methanol and ammoniawhich have been conventionally used, as in Patent Literatures 1 and 2,there is a possibility that unreacted ammonia (also referred to as leakammonia) reacts with the S content to precipitate ammonium sulfate,ammonium hydrogen sulfate or the like. The ammonium sulfate may beprecipitated in a heat transfer tube or a coil in the heat exchangerwhich heat-exchanges the flue gas and the natural gas, and may block theinterior of the piping through which the flue gas passes, therebyincreasing the pressure loss. The ammonium hydrogen sulfate may causecorrosion in the heat exchanger which heat-exchanges the flue gas andthe natural gas, and the material which forms the piping through whichflue gas passes. In contrast, in the present embodiment, since the Scontent does not exist in the flue gas 22 discharged from the reformer14, even if the reducing agent 29 such as ammonia is supplied to theflue gas discharging line L12 on the upstream side of thedenitrification device 15, it is possible to suppress ammonium sulfate,ammonium hydrogen sulfate or the like from being produced by thereaction of the reducing agent 29 such as unreacted ammonia with the Scontent. Thus, it is possible to suppress an increase in pressure lossin the flue gas discharging line L12, and the corrosion in the passageof the flue gas discharging line L12, due to deposition of ammoniumsulfate, ammonium hydrogen sulfate or the like in the flue gasdischarging line L12.

Also, in order to cope with environmental regulations or the like,although the CO₂ recovery device 18 is provided to remove CO₂ containedin the flue gas 22, in the methods for manufacturing methanol andammonia which have been conventionally used, as in Patent Literatures 1and 2, it is necessary to provide the desulfurization device on theupstream side in the gas flow direction of the flue gas from the CO₂recovery device, and the sulfur concentration in the flue gas at theinlet of the CO₂ recovery device is required to set to a predeterminedvalue (for example, 1 ppm) or lower. Also, the number of the devices tobe installed increases as much as the desulfurization device, adisposition location of each device is limited, and the installationcost increases. In contrast, in the present embodiment, since the Scontent does not exist in the flue gas 22 discharged from the reformer14, it is possible to recover CO₂ in the flue gas 22, without installingthe desulfurization device on the upstream side in the gas flowdirection of the flue gas 22 from the CO₂ recovery device 18. Therefore,it is possible to reduce the equipment costs required for recovering CO₂in the flue gas 22.

In addition, in the present embodiment, the reforming device 10 isconfigured so that the first heat exchanger 12 and the second heatexchanger 16 are provided in the flue gas discharging line L12, but isnot limited thereto, and the reforming device 10 may be provided with aplurality of heat exchangers for performing the heat-exchange by theflue gas 22.

FIG. 2 is a diagram illustrating an example of another configuration ofthe reforming device 10. As illustrated in FIG. 2, the flue gasdischarging line L12 has a third heat exchanger (heat exchange unit) 19that is interposed between the first heat exchanger 12 and the secondheat exchanger 16.

The third heat exchanger 19 is a heat exchanger that saves heat of feedwater 75 to be supplied to a steam generation unit 70. By providing thethird heat exchanger 19 between the first heat exchanger 12 and thesecond heat exchanger 16, it is possible to increase the amount of waterand the amount of heat of the feed water 75 to be supplied to the steamgeneration unit 70.

Further, as illustrated in FIG. 3, a fourth heat exchanger (heatexchange unit) 20 is provided between the compressor 11 of the rawmaterial gas supply line L13-2 and the first heat exchanger 12 to saveheat of the natural gas 21 to be supplied to the first heat exchanger12, by the branched natural gas 21 a after the desulfurization.

By keeping the natural gas 21 to be introduced into the first heatexchanger 12 to the high-temperature side in advance, the fourth heatexchanger 20, which performs the heat-exchange between the natural gases21, can reduce the amount of recovery heat of the flue gas 22 after theheat exchange to increase the amount of recovery heat in the third heatexchanger 19, as compared to the system illustrated in FIG. 2.

In addition, by raising the temperature of the flue gas 22 to beintroduced into the third heat exchanger 19, it is possible to improvethe temperature difference of the fluid to be heat-exchanged, therebyreducing the heat transfer area of the third heat exchanger 19.

In addition, in the present embodiment, the reforming device 10 isequipped with only one reformer 14, but is not limited thereto, and aplurality of reformers 14 may be equipped. FIG. 4 is a diagramillustrating an example of another configuration of the reforming device10. As illustrated in FIG. 4, the reformer 14 may have a first reformer14-1 and a second reformer 14-2.

As illustrated in FIG. 4, the first reformer 14-1 is intended to supplythe vapor 24 to the desulfurized and compressed natural gas 21 andprimarily reform hydrocarbon in the natural gas 21 to either one or bothof H₂ and CO or H₂ and CO₂. The first reformer 14-1 has the sameconfiguration as that of the first reformer 14 illustrated in FIG. 1,and has a main body 14 a (not illustrated in FIG. 4), a catalystreaction tube 14 b (not illustrated in FIG. 4) and a burner 14 c (notillustrated in FIG. 4). The catalyst reaction tube 14 b is heated by theflue gas 22 generated by combustion in the burner 14 c, and theintroduced natural gas 21 comes into contact with the reforming catalystwhen passing through the reforming catalyst layer of the catalystreaction tube 14 b, and thus, as in the above-described formulas (3) and(4), hydrocarbon in the natural gas 21 is subjected to vapor-reformingto either one or both of H₂ and CO or H₂ and CO₂.

After the natural gas 21 is primarily reformed in the first reformer14-1, it is supplied to the second reformer 14-2.

The second reformer 14-2 is intended to supply air (oxygen) to thereformed gas 23, and secondarily reform hydrocarbon in the reformed gas23 using a partial oxidation reaction. The heated combustion air 26 isintroduced into the second reformer 14-2 from the outside, andhydrocarbon in the reformed gas 23 is secondarily reformed to either oneor both of H₂ and CO or H₂ and CO₂.

FIG. 5 is a diagram illustrating an example of another configuration ofthe reforming device 10. As illustrated in FIG. 5, the reformer 14 mayhave a pre-reformer 14-3, the first reformer 14-1, and the secondreformer 14-2.

The pre-reformer 14-3 is intended to supply the vapor 24 to the naturalgas 21 and primarily reform hydrocarbon in the natural gas 21 to eitherone or both of H₂ and CO or H₂ and CO₂. The pre-reformer 14-3 has a mainbody, and a reforming catalyst layer having a reforming catalysttherein. Also, the pre-reformer 14-3 is connected to the vapor supplyline L14. The vapor 24 is supplied into the pre-reformer 14-3 throughthe vapor supply line L14, and is mixed with the natural gas 21. Afterthe natural gas 21 is mixed with the vapor 24 in the main body, thenatural gas 21 is supplied to the reforming catalyst layer. The naturalgas 21 comes into contact with the reforming catalyst when passingthrough the reforming catalyst layer in the pre-reformer 14-3, and thus,as in the above-described formulas (3) and (4), hydrocarbon in thenatural gas 21 is primarily reformed to either one or both of H₂ and COor H₂ and CO₂.

When the reformer 14 is constituted by three stages of the firstreformer 14-1, the second reformer 14-2 and the pre-reformer 14-3, apart or all of the flue gas 22 discharged from the first reformer 14-1may be used as a heating medium for heating the reforming catalyst layerof the pre-reformer 14-3.

FIGS. 6 to 8 are diagrams illustrating modified examples of anotherconfiguration of the reforming device 10.

In this embodiment, the raw material gas branching line L11 is providedso as to be connected to the air supply line L15 so that the natural gas21 and the combustion air 26 are supplied to the reformer 14 through theair supply line L15, but is not limited thereto, and as illustrated inFIG. 6, the raw material gas branching line L11 may be directlyconnected to the reformer 14 so that the natural gas 21 and thecombustion air 26 are separately supplied into the reformer 14.

In addition, in the present embodiment, although the raw material gasbranching line L11 is provided so as to be connected to the downstreamside of the desulfurization device 13 with respect to the flow directionof the natural gas 21, but is not limited thereto, and as illustrated inFIG. 7, a raw material gas branching line L21 for connecting theupstream side of the desulfurization device 13 with the air supply lineL15 may be provided such that the raw material gas branching line L21extracts the branch gas 21 b of a part of the natural gas 21 from theupstream side of the desulfurization device 13 with respect to the flowdirection of the natural gas 21.

In addition, as illustrated in FIG. 8, the raw material gas branchinglines L11 and L21 may be provided so as to extract 21 a of a part of thenatural gas 21 from the upstream side and the downstream side of thedesulfurization device 13 with respect to the flow direction of thenatural gas 21.

Furthermore, in the present embodiment, the reforming device 10 isequipped with the denitrification device 15, but is not limited thereto,and the reforming device 10 may not be equipped with the denitrificationdevice 15.

Furthermore, in the present embodiment, the reforming device 10 isequipped with the cooling device 17 and the CO₂ recovery device 18, butis not limited thereto, and the reforming device 10 may not be equippedwith these devices in a case where there is no need for recovery of CO₂contained in the flue gas 22.

As described above, since the reforming device 10 has thecharacteristics as described above, it can be used for manufacturing thechemical products, using the reformed gas 23 obtained in the reformingdevice 10. Specifically, the chemical products include, for example,ammonia, methanol, urea, hydrogen, and liquid fuel of liquid hydrocarbonsuch as wax, diesel oil, kerosene, and gasoline by FT synthesis. Inparticular, by applying the reforming device 10 to the manufacturingsystem of ammonia and methanol and the manufacturing system of urea andmethanol, it is possible to improve the manufacturing efficiency ofmethanol and ammonia, and the manufacturing efficiency of urea andmethanol.

FIGS. 9 and 10 are diagrams illustrating examples of systemconfigurations of the reforming device illustrated in FIG. 1 and thereforming device illustrated in FIG. 3.

FIG. 9 is an example of a system configuration corresponding to thereforming device illustrated in FIG. 1, and the flue gas 22 introducedinto the flue gas discharging line L12 from the reformer 14 isheat-exchanged in a plurality of heat exchange units provided inside theflue gas duct.

First, as illustrated in FIG. 9, in the first heat exchanger 12 thatinitially heat-exchanges the natural gas 21 compressed by the compressor11 and having the temperature (T₁₀=50° C.), the natural gas 21 isheat-exchanged with the flue gas 22 having the temperature (T₁=320° C.).The natural gas 21 introduced into the first heat exchanger 12 isheat-exchanged to a high temperature from the temperature (T₁₀=50° C.)to the temperature (T₁₂=300° C.). Thereafter, the heated natural gas 21passes through the desulfurization device 13, is further heat-exchangedin a heat exchanger (not illustrated), and is introduced into thereformer 14 side. Although the flue gas 22 from the reformer 14 isdischarged at a high temperature of the temperature (T0=1050° C.), theflue gas 22 is heat-recovered by a heat exchanger (not illustrated), andbecomes to have the temperature of about 320° C. on a downstream side ofthe denitrification device 15.

The flue gas 22 after the heat-exchange in the first heat exchanger 12is lowered to a temperature (T₂=230° C.), and on the downstream side ofthe flue gas discharging line L12, the flue gas 22 is heat-exchangedwith the combustion air 26 in the second heat exchanger 16. Through theheat-exchange in the second heat exchanger 16, the flue gas 22 islowered to a temperature (T₄=120° C.) from a temperature (T₂=230° C.) toheat the combustion air 26. By the heat-exchange in the second heatexchanger 16, the combustion air 26 can have a high temperature from atemperature (T₂₁=35° C.) to a temperature (T₂₁=170° C.) Since thetemperature of the reformer 14 becomes a high temperature side, it ispossible to reduce an amount of branch of the natural gas 21 to beintroduced into the reformer 14 in the flue gas discharging line L12,thereby improving the amount of introduction of the natural gas 21 forreforming.

FIG. 10 is an example of the system configuration corresponding to thereforming device illustrated in FIG. 3.

In this example, the natural gas 21 compressed by the compressor 11 andhaving a temperature (T₁₀=50° C.) is initially heat-exchanged by anatural gas 21 a (temperature T₁₃=350° C.) of a part of the natural gas21 in a fourth heat exchanger 20. As a result of the heat-exchange inthe fourth heat exchanger 20, the natural gas 21 can be heated from thetemperature (T₁₀=50° C.) to the temperature (T₁₁=120° C.). The heatednatural gas 21 is then heat-exchanged with the flue gas 22 having thetemperature (T₁=350° C.) in the first heat exchanger 12 and is heated toa temperature (T₁₂=290° C.). The heated natural gas 21 is then heated toabout 360° C. by a heat exchanger which is not illustrated, passesthrough the desulfurization device 13, is further heat-exchanged in aheat exchanger which is not illustrated, and is introduced into thereformer 14 side. Although the flue gas 22 from the reformer 14 isdischarged at a high temperature of the temperature (T0=1050° C.), theflue gas 22 is heat-recovered by a heat exchanger (not illustrated), andbecomes to have the temperature of about 350° C. on the downstream sideof the denitrification device 15.

The flue gas 22 after the heat-exchange in the first heat exchanger 12is lowered to a temperature (T₂=290° C.), and on its downstream side,the flue gas 22 is heat-exchanged with the feed water 75 to beintroduced into the steam generation unit 70 in the third heat exchanger19. By the heat-exchange with the feed water 75 in the third heatexchanger 19, the flue gas 22 is lowered from a temperature (T₂=290° C.)to a temperature (T₃=160° C.), thereby heating the feed water 75 from atemperature (T₃₁=130° C.) to a temperature (T₃₂=260° C.). The heatedfeed water 75 is introduced into the steam generation unit 70.

Thereafter, the flue gas 22 having the temperature (T₃=160° C.) afterthe heat-exchange in the third heat exchanger 19 is heat-exchanged withthe combustion air 26 in the second heat exchanger 16. Through theheat-exchange in the second heat exchanger 16, the flue gas 22 islowered from a temperature (T₂=160° C.) to a temperature (T₄=120° C.),thereby heating the combustion air 26. Through the heat-exchange in thesecond heat exchanger 16, the combustion air 26 is heated from atemperature (T₂₁=35° C.) to a temperature (T₂₁=85° C.)

In this example, by heating the feed water 75 to be introduced into thesteam generation unit 70 in the third heat exchanger 19, it is possibleto obtain the boiler feed water having a temperature (T₃₂=260° C.), andit is possible to increase the overall amount of steam generation.

As a result, since the amount of water of the feed water 75 of the vaporgeneration to be introduced into the steam generation unit 70 increasesby the reforming system of FIG. 10, the amount of steam generation isimproved by about 20t/h compared to the case of the reforming system ofFIG. 9, and it is possible to achieve a reduction of 1.9% in the productbasic unit of ammonia (Gcal/ton-NH₃) including the installation of anauxiliary boiler.

Second Embodiment <Manufacturing Device of Chemical Products>

Next, an example of the case of applying the reforming device 10according to the first embodiment illustrated in FIG. 1 to themanufacturing device of chemical products will be described withreference to the drawings. The manufacturing device of chemical productshas the reforming device 10, and a chemical product generation unit thatmanufactures the chemical products using the reformed gas 23 obtained bythe reforming device 10. In this embodiment, the case of manufacturingammonia, methanol or urea as the chemical products will be described.

[Manufacturing Example of Ammonia]

FIG. 11 is a schematic diagram of a chemical product manufacturingdevice equipped with the reforming device according to a secondembodiment of the present invention. In the present embodiment, thereforming device having the two-stage configuration illustrated in FIG.4 is used. Since the same configurations as those of the reformingdevice according to the first embodiment illustrated in FIG. 4 areidentical, the repeated description will not be provided. In thisexample, the reformer is configured so that the primary reformer 14 hasa primary reformer 14-1 and a secondary reformer 14-2, but the presentinvention is not limited thereto.

As illustrated in FIG. 11, a chemical product manufacturing device 40for manufacturing ammonia has a reforming device 10, a steam generationunit 70, a CO shift reaction device (CO shift reaction unit) 41, acarbon dioxide removal device (carbon dioxide removal unit) 42, amethanation device (methanation unit) 43, a compressor 44, a hydrogenseparation device (hydrogen separation unit) 45, an ammonia synthesisunit 46, a cooling unit 72, and a separation unit 73. In addition, inthe present embodiment, the CO shift reaction device 41, the carbondioxide removal device 42, the methanation device 43, compressors 44-1and 44-2, the hydrogen separation device 45 and the ammonia synthesisunit 46 form a chemical product generation unit.

In addition, two first and second preliminary heating units 76-1 and76-2, which preliminarily heat the feed water 75 to be supplied to thesteam generation unit 70, are interposed between the CO shift reactiondevice (CO shift reaction unit) 41 and the carbon dioxide removal device(carbon dioxide removal unit) 42, and between the ammonia synthesis unit46 and the cooling unit 72. In addition, in FIG. 11, a steam header 80supplies the vapor obtained by the steam generation unit 70.Furthermore, the vapor from an auxiliary boiler or the like is alsointroduced into the steam header, and a required amount of vapor is sentto each vapor supply destination from here.

(Steam Generation Unit)

The steam generation unit 70 is intended to supply the vapor 24 to thesteam header 80 in the system. The steam generation unit 70 is providedwith a waste heat recovery boiler (WHB) which recovers the waste heat ofthe reformed gas 23, and a superheater. After the steam generation unit70 thermally heats the feed water 75 by the waste heat to obtain theheated vapor, the steam generation unit 70 further overheats the heatedvapor by the superheater and sends the vapor 24 to the steam header 80.In addition, in this system, the waste heat recovery boiler may befurther installed on the downstream side of the passage line of thereformed gas 23 and on the downstream side of the ammonia synthesis unit46 to recover the heat, but the waste heat recovery boiler is notprovided in this embodiment.

(CO Shift Reaction Device)

The CO shift reaction device 41 is intended to convert (shift) CO in thereformed gas 23 to CO₂ and generate a shift gas 51 containing CO₂. Asthe CO shift reaction device 41, for example, a CO shift reactorequipped with a filling unit filled with the CO shift reaction catalystwhich converts (shift) CO to CO₂ is used.

The reformed gas 23 obtained by reforming the natural gas 21 in thereforming device 10 is discharged from the reforming device 10 and issupplied to the CO shift reaction device 41. In the CO shift reactiondevice 41, as in the following formula (6), CO in the reformed gas 23 isconverted to CO₂ to generate a shift gas 51 containing CO₂. In addition,the gas temperature of the shift gas 51 is, for example, in the range of150° C. to 1000° C.

CO+H₂O→CO₂+H₂   (6)

The shift gas 51 generated by the CO shift reaction device 41 isdischarged from the CO shift reaction device 41 and is supplied to thecarbon dioxide removal device 42.

(Carbon Dioxide Removal Device)

The carbon dioxide removal device 42 is intended to remove carbondioxide (CO₂) in the shift gas 51. As the carbon dioxide removal device42, for example, a device which removes CO₂ in the shift gas 51 byutilizing a chemical adsorption using CO₂ absorbent such as an aminesolvent, a device having catalyst for removing CO₂, a membraneseparation device having a separation membrane which separates CO₂ inthe shift gas 51 or the like is used. The carbon dioxide removal device42 removes CO₂ in the shift gas 51 to generate a CO₂ removal gas 52 fromwhich CO₂ is removed. Also, the gas temperature of the CO₂ removal gas52 is, for example, about 50° C.

The carbon dioxide removal device 42 separates CO₂ from the shift gas51. In addition, separated CO₂ may be used as a gas for methanolsynthesis.

The CO₂ removal gas 52 discharged from the carbon dioxide removal device42 is supplied to the methanation device 43.

(Methanation Device)

The methanation device 43 is intended to convert CO₂ in the CO₂ removalgas 52, from which CO₂ is removed by the carbon dioxide removal device42, into methane. As the methanation device 43, for example, amethanation reactor (methanator) having a catalyst portion filled withmethanation catalyst inside or the like is used. The reactiontemperature (methanation temperature) at the catalyst portion ispreferably 220° C. or higher and 450° C. or lower, and more preferably,290° C. or higher and 350° C. or lower, from the viewpoint of the limittemperature at which the methanation catalyst can be used.

In the methanation device 43, as in the following formula (7), CO₂ inthe CO₂ removal gas 52 is converted into methane to generate a CO₂removal gas 53 containing methane.

CO₂+4H₂→CH₄+2H₂O   (7)

The CO₂ removal gas 53 discharged from the methanation device 43 issupplied to the compressor 44.

(Compressor)

The compressor 44 is intended to compress the CO₂ removal gas 53.

After raising the pressure of the CO₂ removal gas 53 by the compressor44, the CO₂ removal gas 53 is supplied to the hydrogen separation device45.

(Ammonia Synthesis Unit)

The ammonia synthesis unit 46 is intended to manufacture ammonia (NH₃)55 after converting CO₂ in the CO₂ removal gas 53 into methane by themethanation device 43. It is possible to use an ammonia synthesis unit46 that has been generally used hitherto, and, for example, it ispossible to adopt an ammonia synthesis reactor in which the catalyst isdisposed on one or more beds in the reactor. A method for synthesizingammonia by causing the CO₂ removal gas 53 as a synthesis gas containingnitrogen (N₂) and hydrogen to flow through the ammonia synthesis reactoris used.

In the ammonia synthesis unit 46, as in the following formula (8),nitrogen and hydrogen in the CO₂ removal gas 53 react with each other togenerate ammonia 55.

N₂+3H₂→2NH₃   (8)

After the ammonia composite obtained in the ammonia synthesis unit 46passes through the second preheating unit 76-2, the ammonia composite iscooled by the cooling unit 72, and the objective ammonia 55 is separatedby the separation unit 73.

In this way, according to the chemical product manufacturing device 40for manufacturing ammonia, it is possible to improve the thermalefficiency when reforming the natural gas 21 by providing theabove-described reforming device 10, and it is possible to suppress anoccurrence of corrosion in the passage of the flue gas discharging lineL12 in the course of processing the flue gas 22. Therefore, according tothe chemical product manufacturing device 40 that manufactures ammonia,it is possible to stably produce the ammonia 55 and to improve theproduction efficiency of the ammonia 55.

Moreover, since the sulfur content is removed in the desulfurizationdevice 13, it is possible to lower the temperature of the flue gas 22after the heat exchange to 120° C., and it is possible to increase theheat exchange efficiency in the second heat exchanger 16 of the flue gasdischarging line L12. That is, since the sulfur content is not removedin the related art, the temperature of the flue gas 22 can only belowered to about 175° C., the amount of introduction of the branch fuelincreases accordingly, and as a result, the amount of production of thereformed gas decreases.

Therefore, according to the chemical product manufacturing device of thepresent embodiment, since it is possible to raise the temperature of thecombustion air 26 to be introduced into the reformer 14, it is possibleto reduce an amount of branch of the natural gas 21 that is introducedto the reformer 14 by being branched. As a result, since it is possibleto achieve an increase in the amount of production of the reformed gas,it is possible to increase the amount of manufacturing of ammonia.

In this way, in this embodiment, since the amount of branch of thebranch gas in the raw material gas branching line L11 of the natural gas21 is reduced, the amount of introduction of the natural gas 21 to beintroduced into the reformer 14 is improved by 8.5%. As a result, it isalso possible to achieve reduction of 1.1% in the product basic unit(Gcal/ton-NH₃) as for an overall efficiency of the plant.

Next, the chemical product manufacturing device using the reformingdevice illustrated in FIG. 3 of the above-described embodiment will bedescribed. FIG. 12 is a schematic diagram of the chemical productmanufacturing device equipped with the reforming device illustrated inFIG. 3 according to the second embodiment of the present invention. Inaddition, the reforming device illustrated in FIG. 3 is configured sothat the reformer 14 is one stage, but in this example, a reformer of atwo-stage configuration is adopted as illustrated in FIG. 4.

In the reforming device 10 of the chemical product manufacturing device40 illustrated in FIG. 12, a third heat exchanger 19 is interposedbetween the first heat exchanger 12 and the second heat exchanger 16provided in the flue gas discharging line L12. Thus, since it ispossible to heat the feed water 75 supplied to the steam generation unit70 by the third heat exchanger 19, the amount of generation of vaporgreatly increases. In addition, in the reforming device 10 illustratedin FIG. 12, a steam superheater 89, which heat-exchanges the vapor 24from the steam generation unit 70, is provided in the flue gasdischarging line L12. Thus, since the vapor 24 supplied to the steamheader 80 is overheated by the flue gas 22 of a high temperature (forexample, 890° C.), the temperature of the vapor can be set to a highertemperature (for example, 515° C.)

Thus, in the chemical product manufacturing device as illustrated inFIG. 11, for example, when the amount of vapor generation isinsufficient, by providing a separate auxiliary boiler, the vapor issupplied by the auxiliary boiler. However, in the chemical productmanufacturing device illustrated in FIG. 12, since the amount of vaporgeneration greatly increases, the auxiliary boiler may not be requiredor the auxiliary boiler can be significantly reduced in size.

Thus, according to the chemical product manufacturing device 40 formanufacturing ammonia, it is possible to improve the thermal efficiencywhen reforming the natural gas 21 by providing the reforming device 10,and it is possible to suppress an occurrence of corrosion in the passageof the flue gas discharging line L12 in the course of processing theflue gas 22. Therefore, according to the chemical product manufacturingdevice 40 of the present embodiment, it is possible to stably producethe ammonia 55 and to improve the production efficiency of the ammonia55.

[Manufacturing Example of Urea]

FIG. 13 is a schematic diagram of the chemical product manufacturingdevice equipped with the reforming device according to the secondembodiment of the present invention.

FIG. 13 is a schematic diagram of a manufacturing system of urea andmethanol according to the second embodiment of the present invention. Asillustrated in FIG. 13, a chemical product manufacturing device 40 formanufacturing urea is further equipped with a urea synthesis unit 61 anda carbon dioxide branching supply line L33, in the chemical productmanufacturing device 40 illustrated in FIG. 12.

The urea synthesis unit 61 is provided on the downstream side in theammonia flow direction of the ammonia synthesis unit 46. The ureasynthesis unit 61 is intended to synthesize a urea 62 using the ammonia55 obtained in the ammonia synthesis unit 46. It is possible to use theurea synthesis unit 61 which has been generally used hitherto, and forexample, it is possible to adopt a urea synthesis tube in which ammoniaand CO₂ react with each other in the tube.

The carbon dioxide branching supply line L33 is a line that introducesCO₂, which has been removed by the carbon dioxide removal device 42,into the urea synthesis unit 61.

The ammonia 55 obtained in the ammonia synthesis unit 46 is supplied tothe urea synthesis unit 61. In addition, the ammonia 55 is supplied fromthe carbon dioxide removal device 42 to the urea synthesis unit 61 fromthe carbon dioxide supply line L33.

In the urea synthesis unit 61, the ammonia 55 obtained in the ammoniasynthesis unit 46 and CO₂ separated by the carbon dioxide removal device42 react with each other as in the following reaction formula (9) tosynthesize urea (NH₂(CO)NM₂).

2NH₃+CO₂→NH₂(CO)NH₂+H₂   (9)

Thus, in the chemical product manufacturing device 40 that manufacturesurea, it is possible to manufacture the urea 62, using the ammonia 55obtained in the ammonia synthesis unit 46 and CO₂ separated by thecarbon dioxide removal device 42 during the ammonia synthesis.

In this way, similar to the chemical product manufacturing device 40that manufactures ammonia according to the second embodiment, accordingto the chemical product manufacturing device 40 that manufactures urea,by providing the reforming device 10 of the first embodiment, it ispossible to improve the thermal efficiency when reforming the naturalgas 21, and it is possible to suppress an occurrence of corrosion in thepassage of the flue gas discharging line L12 in the course of processingthe flue gas 22. Therefore, according to the chemical productmanufacturing device 40 that manufactures urea, it is possible to stablyproduce the urea 62 and to improve the production efficiency of the urea62.

[Simultaneous Manufacturing Example of Ammonia and Methanol]

FIG. 14 is a schematic diagram of the chemical product manufacturingdevice equipped with the reforming device according to a secondembodiment of the present invention. In the above-described embodiments,ammonia or urea has been manufactured alone. However, in the presentembodiment, as the chemical product manufacturing device, a devicecapable of simultaneously manufacturing methanol as well as ammonia isprovided.

As illustrated in FIG. 14, the chemical product manufacturing device 40for manufacturing of ammonia and methanol has a reforming device 10, aCO shift reaction device (CO shift reaction unit) 41, a carbon dioxideremoval device (carbon dioxide removal unit) 42, a methanation device(methanation unit) 43, first and second compressors 44-1 and 44-2, anammonia synthesis unit (ammonia synthesis unit) 46, and a methanolsynthesis unit 47.

In the chemical product manufacturing device 40 of the presentembodiment, the methanol synthesis unit 47 is installed on the upstreamside of the methanation device 43. Moreover, as the compressor 44, thefirst compressor 44-1 is installed between the carbon dioxide removaldevice 42 and the methanol synthesis unit 47, and the second compressor44-2 is installed between the methanation device 43 and the ammoniasynthesis unit 46. Furthermore, in this embodiment, although thecompressor 44 has a two-stage configuration, it may have a plurality ofstages such as a three-stage configuration of a low-pressure compressor,an intermediate-pressure compressor and a high-pressure compressor.

(Methanol Synthesis Unit)

The methanol synthesis unit 47 is intended to synthesize the methanol 56that uses carbon dioxide and hydrogen in the reformed gas 23 obtained inthe reforming device 10 as a raw material. It is possible to use themethanol synthesis unit 47 that has been generally used hitherto, andfor example, a methanol synthesis device having a catalytic reactor orthe like is used.

Here, carbon dioxide in the reformed gas 23 as a methanol production rawmaterial adjusts its content, by providing bypass lines L35 and L36 eachhaving on-off valves V₁ and V₂ that partially bypass the CO shiftreaction device 41 and the carbon dioxide removal device 42.

In the methanol synthesis unit 47, as in the following formulas (10) and(11), hydrogen and carbon monoxide in the reformed gas 23 react witheach other and hydrogen and carbon dioxide react with each other toproduce the methanol 56.

2H₂+CO→CH₃OH   (10)

3H₂+CO₂→CH₃OH+H₂O   (11)

Thus, according to the chemical product manufacturing device 40 thatmanufactures ammonia and methanol, it is possible to obtain the ammonia55 obtained in the ammonia synthesis unit 46 and the methanol 56obtained in the methanol synthesis unit 47, and it is possible tosimultaneously manufacture the ammonia 55 and the methanol 56 inparallel.

Thus, according to the chemical product manufacturing device 40 thatmanufactures ammonia and methanol, by providing the reforming device 10of the first embodiment, similar to the chemical product manufacturingdevice 40 that manufactures ammonia according to the second embodiment,it is possible to improve the thermal efficiency when reforming thenatural gas 21 and it is possible to prevent the occurrence of corrosionin the passage of the flue gas discharging line L12 in the course ofprocessing the flue gas 22. Therefore, according to the chemical productmanufacturing device 40 that manufactures urea, it is possible to stablyproduce the ammonia 55 and the methanol 56 and to improve theirproduction efficiency.

[Simultaneous Manufacturing Example of Urea and Methanol]

FIG. 15 is a schematic diagram of a chemical product manufacturingdevice equipped with the reforming device according to the secondembodiment of the present invention. Although ammonia and methanol havebeen manufactured in the above-described embodiments, in thisembodiment, as a chemical product manufacturing device, there isprovided a device capable of manufacturing urea and simultaneouslymanufacturing methanol, by using ammonia as a raw material.

In the chemical product manufacturing device 40 of FIG. 14, the ammonia55 obtained in the ammonia synthesis unit 46 is further introduced intothe urea synthesis unit 61 to manufacture urea.

Thus, according to the chemical product manufacturing device 40 thatmanufactures urea and methanol, it is possible to obtain the urea 62using the ammonia 55 obtained in the ammonia synthesis unit 46 as a rawmaterial, and the methanol 56 obtained in the methanol synthesis unit47, and it is possible to simultaneously obtain the urea 62 and themethanol 56 in parallel.

In this way, according to the chemical product manufacturing device 40that manufactures urea and methanol, by providing the reforming device10 of the first embodiment, similar to the chemical productmanufacturing device 40 that manufactures ammonia according to thesecond embodiment, it is possible to improve the thermal efficiency whenreforming the natural gas 21 and it is possible to suppress theoccurrence of corrosion in the passage of the flue gas discharging lineL12 in the course of processing the flue gas 22. Therefore, according tothe chemical product manufacturing device 40 that manufactures urea, itis possible to stably produce the urea 62 and the methanol 56 and toimprove their production efficiency.

[Simultaneous Manufacturing Example of Ammonia and Methanol]

FIG. 16 is a schematic diagram of a chemical product manufacturingdevice equipped with the reforming device according to the secondembodiment of the present invention. In the embodiment of FIG. 14,although methanol has been manufactured by the reformed gas 23, in thepresent embodiment, as the chemical product manufacturing device, adevice capable of manufacturing methanol by the additional methanolsynthesis unit by separating carbon dioxide and hydrogen from thereformed gas 23 is provided.

As illustrated in FIG. 16, a hydrogen separation device 45 is providedbetween the first compressor 44-1 and the second compressor 44-2.

(Hydrogen Separation Device)

The hydrogen separation device 45 provided between the first compressor44-1 and the second compressor 44-2 is intended to separate a part ofhydrogen (H₂) contained in the CO₂ removal gas 53 from the CO₂ removalgas 53. The hydrogen separation device 45 is a membrane separationdevice having a hydrogen-permeable function membrane. In thisembodiment, the hydrogen-permeable function membrane is a membrane forseparating at least a part of hydrogen (H₂) contained in the gas.

As the hydrogen-permeable function membrane, for example, it ispreferred to use a palladium (Pd) membrane, a polymer membrane such aspolysulfone, polyamide or polyimide, or a membrane obtained by aplurality of bundles of elements formed into a hollow fiber. As thehydrogen-permeable function membrane, it is possible to adopt the mostsuitable design, based on the material, the use condition, the life, thehydrogen permeation coefficient, and the selection rate.

In the hydrogen separation device 45, since the CO₂ removal gas 53transmits through the hydrogen-permeable function membrane, hydrogencontained in the CO₂ removal gas 53 is separated by the hydrogenpermeable function membrane. The CO₂ removal gas 53 in which hydrogen isseparated by the hydrogen separation device 45 is discharged from thehydrogen separation device 45.

The hydrogen separation device 45 is connected to the hydrogen supplyline L32, a part of hydrogen (H₂) separated from the shift gas 51 in thehydrogen separation device 45 is supplied to the methanol synthesis unit47 through the hydrogen supply line L32, and is used as a gas formethanol synthesis.

In addition, in this embodiment, as the hydrogen separation device 45, amembrane separation device equipped with the hydrogen-permeable functionmembrane is used, but is not limited thereto, and, for example, it ispossible to use a pressure swing adsorption device (PSA) or the like,and any device capable of separating at least a part of hydrogencontained in the CO₂ removal gas 53 may be used.

The CO₂ removal gas 53 discharged from the hydrogen separation device 45is supplied to the second compressor 44-2. After the pressure of the CO₂removal gas 53 is appropriately adjusted to a pressure suitable forammonia synthesis in the second compressor 44-2, the CO₂ removal gas 53is supplied to the ammonia synthesis unit 46. Furthermore, hydrogenseparated by the hydrogen separation device 45 is supplied to themethanol synthesis unit 47 through a hydrogen supply line L32.

Hydrogen separated by the hydrogen separation device 45 passes throughthe hydrogen supply line L32, CO₂ separated by the carbon dioxideremoval device 42 passages through the carbon dioxide supply line L31,and hydrogen separated by the hydrogen separation device 45 and carbondioxide (CO₂) separated by the carbon dioxide removal device 42 aresupplied to the methanol synthesis unit 47.

(Methanol Synthesis Unit)

The methanol synthesis unit 47 is intended to synthesize the methanol56, by using carbon dioxide separated by the carbon dioxide removaldevice 42 and hydrogen separated by the hydrogen separation device 45,as the raw materials. It is possible to use the methanol synthesis unit47 that has been generally used hitherto, and for example, a methanolsynthesis device having a catalytic reactor or the like is used.

Thus, according to the chemical product manufacturing device 40 thatmanufactures the ammonia 55 and the methanol 56, it is possible toobtain the ammonia 55 obtained in the ammonia synthesis unit 46, and themethanol 56, by using carbon dioxide separated by the carbon dioxideremoval device 42 and hydrogen separated by the hydrogen separationdevice 45, and it is possible to simultaneously manufacture the ammonia55 and the methanol 56 in parallel.

In this way, according to the manufacturing system 40 that manufacturesammonia and methanol, by providing the reforming device 10, it ispossible to improve the thermal efficiency when reforming the naturalgas 21, and it is possible to suppress the occurrence of corrosion inthe passage of the flue gas discharging line L12 in the course ofprocessing the flue gas 22. Therefore, according to the manufacturingsystem 40 of ammonia and methanol, it is possible to stably produce theammonia 55 and the methanol 56 and to improve the production efficiencyof the ammonia 55 and the methanol 56.

In addition, in the present embodiment, the hydrogen separation device45 is provided between the first compressor 44-1 and the secondcompressor 44-2 to separate hydrogen in all CO₂ removal gas 53 separatedby the hydrogen separation device 45. However, the above-describedconfiguration is not limited, and only a part of the CO₂ removal gas 53separated by the first compressor 44-1 or the second compressor 44-2 maybe supplied to the hydrogen separation device 45 to separate hydrogen inthe CO₂ removal gas 53 by the hydrogen separation device 45.

[Simultaneous Manufacturing of Urea and Methanol]

FIG. 17 is a schematic diagram of a chemical product manufacturingdevice equipped with the reforming device according to the secondembodiment of the present invention. Although the ammonia 55 and themethanol 56 are manufactured in the embodiment of FIG. 16, in thisembodiment, as a chemical product manufacturing device, a device capableof manufacturing urea by the urea synthesis unit 61 from the obtainedammonia 55 is provided.

As illustrated in FIG. 17, according to the chemical productmanufacturing device 40 of this embodiment, the ammonia 55 obtained inthe ammonia synthesis unit 46 is further introduced into the ureasynthesis unit 61 to manufacture urea in the chemical productmanufacturing device 40 of FIG. 14.

According to the chemical product manufacturing device 40 thatmanufactures urea and methanol according to the present embodiment, itis possible to obtain the urea 62 using the ammonia 55 obtained in theammonia synthesis unit 46 as the raw material, and the methanol 56obtained in the methanol synthesis unit 47, and it is possible tosimultaneously manufacture the urea 62 and the methanol 56 in parallel.

Thus, according to the chemical product manufacturing device 40 thatmanufactures urea and methanol, by providing the reforming device 10 ofthe first embodiment, similar to the chemical product manufacturingdevice 40 that manufactures ammonia according to the second embodiment,it is possible to improve the thermal efficiency when reforming thenatural gas 21, and it is possible to suppress the occurrence ofcorrosion in the passage of the flue gas discharging line L12 in thecourse of processing the flue gas 22. Therefore, according to thechemical product manufacturing device 40 that manufactures urea, it ispossible to stably produce the urea 62 and the methanol 56 and toimprove their production efficiency.

[Manufacturing Example of Methanol]

FIGS. 18 and 19 are schematic diagrams of the chemical productmanufacturing device equipped with the reforming device according to thesecond embodiment of the present invention. In the above-describedembodiments, a device for manufacturing only methanol is provided as thechemical product manufacturing device.

As illustrated in FIG. 18, the chemical product manufacturing device 40for manufacturing methanol has a reforming device 10, a steam generationunit 70, a compressor 44, and a methanol synthesis unit 47.

The chemical product manufacturing device 40 of the present embodimentis intended to synthesize the methanol 56, by using carbon dioxide andhydrogen in the reformed gas 23 obtained in the reforming device 10 asthe raw material. It is possible to use the methanol synthesis unit 47that has been generally used hitherto, and for example, a methanolsynthesis device having a catalytic reactor is used.

Further, as illustrated in FIG. 19, the reformer 14 has a two-stageconfiguration, the first reformer 14-1 has the configuration of thereformer of FIG. 1, the second reformer 14-2 is used as an auto-thermalreforming furnace (ATR: Auto Thermal Reformer), and oxygen in place ofair is supplied to the reformer to obtain a reformed gas 23 having a gascomposition that is suitable for methanol synthesis.

In addition, in the above-described second embodiment, although thedescription has been given of a case where ammonia, methanol or urea ismanufactured by alone or in co-production, the second embodiment is notlimited thereto, and it can also be similarly applied to a case whereammonia or urea and other hydrocarbon are simultaneously manufactured inparallel.

Also, the reforming device 10 can also be similarly used in a hydrogenmanufacturing system that manufactures hydrogen, and a system thatmanufactures liquid fuel of liquid hydrocarbon by the FT synthesis.Also, it may be manufactured by combining a plurality of these chemicalproducts.

REFERENCE SIGNS LIST

10 REFORMING DEVICE

11 COMPRESSOR (FIRST COMPRESSION UNIT)

12 FIRST HEAT EXCHANGER (HEAT EXCHANGE UNIT)

13 DESULFURIZATION DEVICE (DESULFURIZATION UNIT)

14 REFORMER (REFORMING UNIT)

14A MAIN BODY

14B CATALYST REACTION TUBE

14C BURNER

14-1 FIRST REFORMER

14-2 SECOND REFORMER

14-3 PRE-REFORMER

15 DENITRIFICATION DEVICE (DENITRIFICATION UNIT)

16 SECOND HEAT EXCHANGER (HEAT EXCHANGE UNIT)

17 COOLING DEVICE

18 CO₂ RECOVERY DEVICE (CO₂ RECOVERY UNIT)

19 THIRD HEAT EXCHANGER (HEAT EXCHANGE UNIT)

20 FOURTH HEAT EXCHANGER (HEAT EXCHANGE UNIT)

21 NATURAL GAS

22 FLUE GAS

23 REFORMED GAS

24 VAPOR

26 COMBUSTION AIR

28 REDUCING AGENT INJECTOR

29 REDUCING AGENT

30 COOLING WATER

40 CHEMICAL PRODUCT MANUFACTURING DEVICE

41 CO SHIFT REACTION DEVICE (CO SHIFT REACTION UNIT)

42 CARBON DIOXIDE REMOVAL DEVICE (CARBONIC DIOXIDE REMOVAL UNIT)

43 METHANATION DEVICE (METHANATION UNIT)

44, 44-1, 44-2 COMPRESSOR

45 HYDROGEN SEPARATION DEVICE

46 AMMONIA SYNTHESIS UNIT

47 METHANOL SYNTHESIS UNIT

51 SHIFT GAS

52, 53 CO₂ REMOVAL GAS

55 AMMONIA

56 METHANOL

61 UREA SYNTHESIS UNIT

62 UREA

L11, L21 RAW MATERIAL GAS BRANCHING LINE

L12 FLUE GAS DISCHARGING LINE

L13-1 to L13-4 RAW MATERIAL GAS SUPPLY LINE

L14 VAPOR SUPPLY LINE

L15 AIR SUPPLY LINE

L31 CARBON DIOXIDE SUPPLY LINE

L32 HYDROGEN SUPPLY LINE

L33 CARBON DIOXIDE BRANCHING SUPPLY LINE

1. A reforming device comprising: a first compression unit thatcompresses a raw material gas containing hydrocarbon and sulfur; a firstheat-exchange unit that heats the compressed raw material gas; adesulfurization unit that removes sulfur content contained in the heatedraw material gas; a reforming unit that reforms the hydrocarbon in theraw material gas to either one or both of H₂ and CO or H₂ and CO₂ togenerate a reformed gas containing either one or both of H₂ and CO or H₂and CO₂; a raw material gas branching line that extracts a part of thecompressed raw material gas from either one or both of an upstream sideand a downstream side of the desulfurization unit with respect to a flowdirection of the raw material gas, and supplies the part of thecompressed raw material gas as a combustion fuel used for heating in thereforming unit; a flue gas discharging line that discharges a flue gas,which is generated by combustion in the reforming unit, from thereforming unit; a second heat-exchange unit that heat-exchanges thecombustion air used for heating in the reforming unit with the flue gaswhich is heat-exchanged in the first heat exchange unit; a third heatexchanger that is provided between the first heat exchange unit and thesecond heat exchange unit and heat-exchanges feed water supplied to asteam generation unit with the flue gas; and a fourth heat exchangerthat is provided in the raw material gas branching line to heat-exchangethe compressed raw material gas before being introduced into the firstheat exchanger with a part of the branched raw material gas, wherein thefirst heat exchange unit is provided in the flue gas discharging line,and the flue gas is used as a heating medium of the compressed rawmaterial gas, and the second heat exchange unit is provided on thedownstream side of the first heat exchange unit of the flue gasdischarging line, and is used as the heating medium of the combustionair by residual heat which is heat-exchanged in the first heat exchangeunit.
 2. The reforming device according to claim 1, wherein thereforming unit has a first reforming unit that supplies vapor to the rawmaterial gas to primarily reform the hydrocarbon in the raw material gasto either one or both of H₂ and CO or H₂ and CO₂, and a second reformingunit that secondarily reforms the hydrocarbon in the raw material gasafter the primary reforming in the first reforming unit to either one orboth of H₂ and CO or H₂ and CO₂ to be a reformed gas, using thecombustion air and the compressed raw material gas supplied from the rawmaterial gas branching line.
 3. (canceled)
 4. (canceled)
 5. Thereforming device according to claim 1, comprising any one or both of: adenitrification unit that is provided between the reforming unit of theflue gas discharging line and the heat exchange unit to remove NOxcontained in the flue gas that is generated in the reforming unit; and aCO₂ recovery unit that is provided on the downstream side of the heatexchange unit with respect to the flow direction of the flue gas of theflue gas discharging line to remove CO₂ contained in the flue gas.
 6. Adevice for manufacturing chemical products comprising: the reformingdevice according to claim 1; and a chemical product generation unit thatmanufactures chemical products using the reformed gas.
 7. The device formanufacturing chemical products according to claim 6, wherein thechemical product generation unit is an ammonia synthesis unit thatsynthesizes ammonia using the reformed gas which has been reformed. 8.The device for manufacturing chemical products according to claim 7,wherein the chemical product generation unit is a urea synthesis unitthat synthesizes urea using the obtained ammonia.
 9. The device formanufacturing chemical products according to claim 6, wherein thechemical product generation unit is a methanol synthesis unit thatsynthesizes methanol using the reformed gas which has been reformed. 10.A reforming method comprising: a first heat-exchange step of heating araw material gas containing compressed hydrocarbon and sulfur; adesulfurization step of removing sulfur content contained in the heatedraw material gas; a reforming step of reforming the hydrocarbon in theraw material gas to either one or both of H₂ and CO or H₂ and CO₂ togenerate a reformed gas containing either one or both of H₂ and CO or H₂and CO₂; a second heat-exchange step of heat-exchanging a combustion airused for heating in the reforming step with the flue gas that isheat-exchanged in the first heat-exchange step; a third heat-exchangestep of heat-exchanging feed water supplied to a steam generation unitwith the flue gas, the third heat-exchange step being performed betweenthe first heat-exchange step and the second heat-exchange step; and afourth heat-exchange step that is performed in a raw material gasbranching line to heat-exchange the compressed raw material gasintroduced into the first heat-exchange step with a part of the branchedraw material gas, wherein the compressed raw material gas is extractedfrom either one or both of an upstream side and a downstream side of thedesulfurization step with respect to a flow direction of the rawmaterial gas, and is supplied as a combustion fuel used for heating inthe reforming step, and the flue gas generated by combustion in thereforming step is discharged from the reforming step, the flue gas issubjected to a first heat-exchange by being used as a heating medium ofthe compressed raw material gas, and the flue gas of residual heat afterheat-exchange of the compressed raw material gas is subjected to asecond heat-exchange as a heating medium of the combustion air. 11.(canceled)
 12. (canceled)
 13. A method for manufacturing chemicalproducts comprising: the reforming step according to claim 10; and achemical product generation step of manufacturing chemical productsusing the reformed gas.
 14. The method for manufacturing chemicalproducts according to claim 13, wherein the chemical product generationstep is an ammonia synthesizing step of synthesizing ammonia using thereformed gas which has been reformed.
 15. The method for manufacturingchemical products according to claim 14, wherein the chemical productgeneration step is a urea synthesizing step of synthesizing urea usingthe obtained ammonia.
 16. The method for manufacturing chemical productsaccording to claim 13, wherein the chemical product generation step is amethanol synthesizing step of synthesizing methanol using the reformedgas which has been reformed.